The present invention concerns X-ray apparatus for examination of a subject, as in radiological diagnosis of a human patient, and particularly X-ray systems in which X-ray radiation is partially masked during a scan of the subject. Systems of this general type are shown in U.S. Pat. Nos. 3,790,291, 4,315,146 and Radiology, 120: 705-711, September 1976. In such systems the X-radiation of the subject is masked by a moving radio-opaque body having a slit transmitting a fan-shaped beam from an X-ray tube source during one scan of the subject yielding one frame of X-ray image while reducing X-ray scatter from the subject.
It is one object of the present invention further to reduce the effect of X-ray scatter from the subject, and the consequent degradation of the X-ray shadow image, and also to improve the quality of the light image derived from the X-ray image.